Can Lasik cure the starburst effect of astigmatism?

It depends on what you mean by "astigmatism" and how bad it is.

"Astigmatism" means the eye is not regular and equal in its focusing ability for every ray of light entering through the pupil. There is "regular" and what used to be called "irregular" astigmatism (now called Higher Order Aberrations). "Regular astigmatism" is what most people mean by the term because that is the only kind of astigmatism corrected by glasses and contact lenses. This type of astigmatism does not typically produce starburst, but rather an oval type of distortion from a point source of light:

Astigmatism blurring

"Starburst" is a particular type of aberration where light rays spread out in some (or all) directions from a point source of light. It is a common distortion in vision from irregularities in the cornea (very common from the radial linear scars in RK surgery).

Starburst blurring from astigmatism

There is not a hard and fast distinction between such visual aberrations as starburst, coma, veiling glare, and others. While regular astigmatism can cause starburst, that is not its typical effect on vision. Only the most technically advanced types of LASIK (such as wavefront) can correct the irregularities in a cornea that are causing these aberrations.

_Written by J. Trevor Woodhams, M.D. - Chief of Surgery, Woodhams Eye Clinic